A number of indolinone derivatives have been found to exhibit pharmaceutical activity. Due to the ability to modulate the protein kinase activity, they have been suggested to treat an number of conditions such as various types of cancer, mastocytosis, allergy associated chronic rhinitis, diabetes, autoimmune disorders, restenosis, fibrosis, psoriasis, von Hippel-Lindau disease, osteoarthritis, rheumatoid arthritis, angiogensis, inflammatory disorders, immunological disorders, and cardiovascular disorders (WO 01/45689, WO 01/60814, WO 99/48868, U.S. Pat. No. 6,316,429, U.S. Pat. Nos. 6,316,635, 6,133,305, and U.S. Pat. No. 6,248,771).
Among the indolinone derivatives those having an amide group on a heterocyclic ring condensed with the indolinone have been of interest. These compounds modulate protein kinase activity and are thus useful in treating diseases relating to abnormal protein kinase activity. A process for preparing the amide derivatives is disclosed in WO 01/60814. An appropriate pyrrole is formylated and subsequently condensed with a 2-indolinone to give a respective 5-(2-oxo-1,2-dihydroindole-3-ylidenemethyl)-1H-pyrrole. If an amide derivative of the pyrrole is desired, a pyrrole having a carboxylic acid group is selected. The carboxylic acid group is reacted with the desired amine in the presence of dimethylformamide, 1-ethyl-3-(3-dimethylamino-propyl)carbodiimide and 1-hydroxybenzotriazole. In example 129 a scale-up procedure is disclosed in which the amidation is conducted in the presence of dimethylformamide, benzotriazole-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate (BOP) and triethylamine.
It is an object of the present invention to provide an improved process for preparing indolinone derivatives which have an amide group on a heterocyclic ring condensed with the indolinone.